A 29-year-old woman presents with gum bleeding, petechiae, and fever of one week's duration. Hemoglobin 8.4 g/dL, WBC 2,100/μL with 40% large blasts containing abundant granules and bundle-shaped cytoplasmic inclusions, platelets 18,000/μL. PT and aPTT are prolonged, fibrinogen 80 mg/dL, D-dimer markedly elevated. What is the most appropriate immediate step?

• A Start standard AML induction with daunorubicin and cytarabine alone first
• B Give prophylactic platelet transfusions only until marrow results return
• C Start all-trans retinoic acid immediately while awaiting cytogenetic confirmation ✓
• D Administer fresh frozen plasma and observe for 48 hours before any cytotoxic therapy

Explanation

The picture is acute promyelocytic leukaemia (APL, FAB M3) with life-threatening DIC. The blasts are abnormal promyelocytes with faggot cells (Auer rod bundles), and coagulopathy is characteristic of t(15;17) PML-RARA disease. ATRA must be started at the earliest suspicion because it triggers differentiation of promyelocytes and rapidly controls DIC; delay is a major cause of early death. Waiting for cytogenetics or giving plasma support alone risks fatal haemorrhage.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.